I am specifically looking for a bottom bracket with an ISIS interface that spins VERY freely. Many of them tend to spin with some effort, not smoothly like a high quality front wheel bearing will. So, if you are using an ISIS bb, what brand/model do you use and how freely does it spin? Thx.
Any bottom bracket that spins VERY freely wouldn’t have enough lubricant to last much more than a month.
jaretj
I don’t think there are any good ISIS BBs. Phil Wood won’t even make them and I’ve read that the ISIS design does not leave enough room between the spindle and the BB shell for efficient and durable bearings. Zipp sells a ~$200 ISIS BB for their crankset that might be worth a look— They claim it is smooth and they’re a solid company. They do tricks with the axle to make some extra room for bearings. I use the FSA Platinum Pro and it’s not bad but no comparison to my other Campy square-taper BBs. (Of course, I did break one FSA PP bottom bracket axle already, so it is even questionable in my book.)
-Marc
The BB is so tightly packed with grease it won’t spin freely? Doesn’t seem completely logical given that other BB types must also be packed yet do spin smoothly. Thoughts?
Thanks for the info. No “good” ISIS BB’s? Say it ain’t so! The design is fundamentally good. Let’s face it, there isn’t a tremendous amount of stress put on the BB relative to what similar sized bearings are exposed to outside of cycling. Has anyone used a KCNC or American Classic?
I also understand that what I’m asking for is purely subjective and that in itself will skew results. But I’ll plod on and attempt to distill any/all responses. Thanks again.
The second generation KCNC scandium ISIS BB is the best spinning BB I’ve felt in a lot of years. It’s made by Token and can be had from the Professional Cycling Discount store on EBay. I have the Ti, the Ti Ceramic, and the Scandium, and the Scandium spins the best.
Chris
While not the best in terms of free spinning axle, before we switched to Mega Exo style cranksets, I also had good luck with FSA Platinum Pro Megaquad (Ti) ISIS bottom brackets but the ‘Pro’ and ‘Ti’ in the title are good for another $50-$60 markup price.
I don’t think there are any good ISIS BBs.
Interesting…and yet if you ask the MTBers they would say they are FAR better than square taper BB’s, and provide a more secure fit than Octalink. More surface contact area between spindles and crank arms result in a more efficient transfer of power over square tapers.
But yes, the new oversized, hollow BB’s are even better.
“The second generation KCNC scandium ISIS BB is the best spinning BB I’ve felt in a lot of years. It’s made by Token and can be had from the Professional Cycling Discount store on EBay. I have the Ti, the Ti Ceramic, and the Scandium, and the Scandium spins the best.”
Funny.
The mechanics at the store I work in universally voted the KCNC/Token Scandium BB the single dumbest weight weenie part seen all year - and that’s quite an accomplishment.
- of course this might have had something to do with the JRA, spindle broken clean-off like someone cut it with a laser condition of the last one to come through the store…
.
Ok. I’ve tried just about every ISIS bottom bracket out there. From the el cheapo to the expensive. The best one I have found is the Token Ultra-lite Carbon-Ti with ceraminc bearings. Once installed and not over-tightened, it spins smooth without the grindy feeling of the other ISIS BB’s I’ve tried. It’s a winner, if you can find one. Use a couple of wraps of teflon tape around the threads before you install it, plus grease of course. No creaking.
~ AB ~
There’s a difference between spinning “smoothly” and “freely”.
Smoothly = good.
Freely = bad.
That would be the first generation one that broke off. I had one of those, and that is how I got the second generation one 
KCNC sent me a new one immediately after I sent them pictures of how mine broke. The new model has smaller diameter bolts and thicker axle. Weights a bit more. Pretty much on-par with the Ti version when you include the bolts.
I think mine were:
138 + 19 = 157 for scandium/scandium.
148 + 21 = 169 for Ti/alum. bolts.
Chris
…I just wrote a long post that included an anecdote recounting my experiences with spoon-feeding a friend, Halos, and stupid-light BB prototypes from the bad-old CNC craze of the early 90’s. At some point, I realized that I was getting dangerously close to crossing Dan’s “don’t slander equipment manufacturers” line, and I nuked the whole thing.
Suffice to say, you won’t see one of those BB’s on any bike I own, sell, repair, or do a fit on.
.
How so? I’m looking for a BB that does both. I don’t care about the brand or the wieght. I just want this thing to have an absolute minimum of drag.
i had the fsa platinum pro shred on me very quickly (3 mos). I then switched to the cheapo truvativ and it’s still going strong. I don’t know if it’s a part I would spend a lot of money on. I think square taper is the best technology but people need to have a new design to sell more bikes. Even the external bbs are shredding and they definitely have more drag than a similar quality square taper. If I could afford it I’d go back to square taper with a phil wood or campy bb and get a decent aluminum compact crank.
Dan
www.aiatriathlon.com
Yeah, I agree - I dont want to spend a lot on this. I have some FSA cranks that I like very much and see no reason to replace - hence the fascination with ISIS bb’s.
After the grease loosens up a bit, every bottom bracket will spin better. I haven’t seen a BB that spins as freely I feel you are seeking.
Yes, the grease will slow it down slightly but we are only looking at a few watts overall in the drivetrain. If you had a BB with very light grease in it, the oil would run out of the wax (or retainers) fairly quickly and you would be left with no lubricants.
Now if there was an oiling system to the BB then you could get away with just oil and the BB would spin very free. I would suppose you would gain maybe a watt or two.
I use a Truvative BB 68X108 - $50.00 and I’ve been pretty happy with it this year.
jaretj
Amen. These external BB’s are the solution to a problem that was not there…I type this as I prepare to install my Record Carbon crankset that Santa got for me.
isn’t the new record an external bb? You don’t happen to have a compact crank for square taper do you?
isn’t the new record an external bb?
I believe that was entirely his point.
You don’t happen to have a compact crank for square taper do you?
Damn - I should have thought of that! Hey RC10 - do you have two? I need 172.5